Drawing-press.



'- No. 678,439. Patnted July l6, I90l.

L. SCHULEB.

DRAWING PRESS.

(Application filed Nov. 30, 1900.)

(No Model.)

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UNITED STATES PATENT OFFICE.

LOUIS SOHULER, OF G O PPINGEN, GERMANY.

DRAWING-PRESS.

SPECIFICATION forming part of Letters Patent No. 678,439, dated J uly 16, 1901. Application filed N0vember 30, 1900- Serial No. 38,16 7. (No model.)

To ctZZ whom, it may concern.-

Be it known that I, LOUIS SOHULER, a subject of the German Emperor, and a resident of Goppingen, Germany, have invented certain new and useful Improvements in Drawing-Presses, of which the' following is a full,- clear, and exact specification.

My invention relates to drawing-presses operating by hydraulic power; and it comprises a drawing-piston combined with a retarding or brake piston, said pistons being connected and arranged in separate cylinders, the surface area of the braking-piston being slightly larger than that of the drawingpiston, so that additional pressure'will be necessary in the cylinder of the drawing-piston after the said piston has been moved to the die before it will perform its operation upon the sheet of material. In my machine the drawing-piston is combined with a third piston carrying the holder for the material. The combined surface area of these pistons is greater than that of the braking'or retarding piston, so that with equal pressure in the two cylinders (said holder-piston being in the same cylinder with the drawing-piston) the holder-piston and drawing-piston will advance to the die as one body. The drawingpiston will be maintained at its rearmost position relative to the holder-piston by the braking-piston, which is of slightly larger area, and after the parts have advanced to the die additional pressure will be necessary in the cylinder of the drawing-piston to advance the same for the drawing operation.

In the drawing the drawing-press is repre sented in vertical section.

a and b are the two pressure-chambers, separated from each other. In the chamber a are the two pistons c 01, one fitting within the other. The piston c carries the sheet-holder e, and the piston d carries the drawing-piston f. In the chamber b is guided the counterpiston g, which is connected with the drawing forcer or piston d by the rod h and which serves as a braking-piston for the forcing-- piston d.

The pressure-chambers a b communicate with the valves '5 and 7a, which are arranged in thehydraulic conduit Z. The valve t',which is advantageously constructed as a double valve, controls the pipe n, leading to the res ervoir m. These valves are opened and closed by levers 0, which are carried on the machine frame and communicate with connecting-rods 10, which can be operated either automatically or by hand. From the pressure-chamber Z) the conduit q leads also to the reservoir m. A brake-valve 0", controlled by-a weight 1; or under spring-pressure, forms a closing means in this conduit.

The action of the drawing-press is as follows: When both valves 2' and 7c occupy their lowest position, so that the conduitlis brought into connection with the pressure-chambers a and b, while the conduit 71 is closed by the valve 2', thepressure-water enters simultane ously into the chambers a and 5, whereby the pistons c and d'ascend, as they present collectively a greater surface to the pressurewater than the counter-piston g, which receives the pressure through the pipe n on its upper side. The piston g exercises a braking action on thedrawing-piston d at the ascent of the pistons c d, and thus prevents it in the usual manner from leading. As in the ascent of the counter-piston g the space for the water in the chamber decreases constantly said water is pressed by the counter-piston through the conduit u to the chamber a, the weight of the valve 1" being great enough to resist this pressure. When the piston c has pressed the sheet-holder with the metal sheets, supported thereon against the bottom die If, the valve is is closed. Now the pressure-water acts only on the piston cl, and not on the piston g, and with greater power than before, the greater power having been produced by increase of the pump-pressure in the pipe Z, as otherwise the counter-pressure of the piston 9, resulting from the weight-pressure on the valve 7", would not be overcome. As a consequence, the drawing stamp ascends and performs the drawing process. The strongly compressed water still left in the chamber b raises the valve r and passes through the conduit q to the reservoir m. However, in order to avoid the counter-pressure of the piston g during the drawing process the brake-valve r can also be raised when the drawing piston ascends alone, and thus the water left in the chamber 1) flows quite unrestrictedly into the reservoir. When the drawing process is fin ished and the three pistons have reached their highest position, the valve 70 is opened again, whereby the pressure liquid acts anew upon the counter-piston g and draws the latter and the drawing-piston (I, as it is a little larger than the latter, downward until the drawing-stamp strikes. When the position of the double valved is changed in such a manner that it stops the supply of the pressure-water to chamber a, but allows the exhaust of the water contained in chamber a through pipe at to the reservoir m, the counter-piston g draws down both pistons c d to their lowest position under the action of the pressure-water. This finishes the whole procedure, and the drawing process can be repeated by reversal of the valve 6.

At the medium position of the valve 71 the press does not act, as the pressure-water can then flow off from the pipe Z immediately into the reservoir through the pipe at.

I claim-- 1. In combination in a drawing-press with the die, astamp-head, a piston connected with the stamp-head, a cylinder for said piston, a braking or retarding piston of larger surface area than that of the drawing-piston, a cylinder for said braking-piston, a connection between the pistons, and conduits leading to the cylinders with means whereby greater pressure may be exerted upon the drawingpiston than upon the braking-piston when the stamp-head has arrived at the die, substantially as described.

2. In combination, the die, the stampinghead, a piston connected with the stampinghead, a cylinder for said piston, a second piston in said cylinder in which the drawingpiston is adapted to move, a braking-piston, a cylinder therefor, the combined area of the two pistons in the drawing-cylinder being greater than that of the braking-piston and the surface area of the braking-piston being greater than that of the drawing-piston alone, the said second piston and drawing-piston being arranged to move together toward the die when equal pressures are in the two cylinders and the drawing piston advancing alone when pressure is exerted thereon in excess of the pressure in the braking-cylinder and means for conveying pressures to the cylinders, substantially as described.

3. In combination, the die, a holder for the material a piston carrying said holder, a stamping-head arranged within the holder, a drawing-piston connected therewith and movable in the holder-piston, a braking-piston connected with the drawing-piston, a cylinder for the braking-piston, the surface area of the holder and drawing pistons being greater than that of the braking-piston, and that of the braking-piston being greater than that of the drawing-piston alone and conduits leading to the cylinders, substantially as described.

In witness whereof I have hereunto set my hand in presence of two Witnesses.

LOUIS SOIIULER.

\Vitnesses:

KARL Boson, JUL. HAEUSSERMANN. 

